DPI (Deep Packet Inspection)

In telecom networks, DPI is the inspection of packet payloads beyond headers to classify applications, enforce policy, and detect threats. In a telecom context, DPI is also used to decode encapsulated GTP-U traffic and to identify abusive flows on mobile data networks.

Categories: SignalingThreats and Attacks

DPI in context

Signaling protocols carry the control-plane instructions that set up calls, register subscribers, hand over sessions and route SMS. SS7, Diameter, GTP-C and SIP are the four dominant families, and interconnect exposure of any of them is treated by GSMA FS.11 / FS.19 / FS.20 as a top-tier telecom risk.

Telecom threats range from opportunistic SMS phishing and SIM swap to nation-state grade location tracking and lawful-interception abuse. The common thread is that most attacks exploit the inherited trust model of legacy signaling. SS7 and Diameter were designed for a closed operator community that no longer exists.

To place DPI in the wider telecom-security picture, review NTA, IPS, Attack Surface Mapping, ISUP, Telecom Penetration Testing and Bidding-Down Attack.

Related terms

Related topic hubs

  • GTP Firewall GSMA FS.20 GTP-C/GTP-U screening on GRX/IPX borders.
  • Signaling Firewall Unified SS7/Diameter/GTP/SMS signaling firewall framework.
  • GTP Security GTP-C/GTP-U threats across S5/S8, N3/N9 and GRX/IPX borders under GSMA FS.20.
  • SS7 Security SS7/MAP/CAP/SCCP attacks and defenses across 2G/3G interconnect.

More from the TelcoSec Glossary

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